Engineers call the air flowing into buildings infiltration, and that flowing out of them exfitration. These movements have a considerable impact on the temperature inside, and can affect the air quality too. However, for our purposes we focus on the relationship between air flow in and out of buildings and energy efficiency.
Air Flow In and Out of Buildings
Building energy-efficiency is a measure of how much power we use to heat and cool our homes and offices, and operate their electronic and electrical systems. Purchasing top-rate equipment helps save money. But the design of our buildings plays a far greater role.
Heating, air-conditioning, and forced-ventilation use electricity (a form of energy) to heat and cool our buildings. And as a result, it costs money to add and remove warm and cool air from offices and homes. The cost of managing air flow in and out of buildings this way becomes expensive over time.
Keeping hot air out is a priority in summer, although residents sometimes forget the impact of the moisture and allergens also flowing in. However, we can’t entirely prevent this happening. We also need to ensure sufficient ventilation for the sake of our health and comfort too.
How a Building Envelope Curtails HVAC Costs
The ‘envelope’ of a building includes all the materials that separate the indoors from the outside. Air flows in (and out) through any openings when the pressure is greater, or lower outside. This differential may be the result of winds gusting, or a difference in internal and external temperature.
This air flow constantly seeks out gaps in the building envelope. These may be anything from open doors and windows, to tiny cracks and crevices left open by careless building contractors cutting corners.
Three Types of Air Flows In and Out Buildings
- Diffuse airflow over a wide area, through porous materials and insulation.
- Orifice airflow through specific openings such as doors and windows.
- Channel airflow, where the entry and exit points are a distance apart.
Channel airflow is the most challenging of these three causes to identify and repair.
Managing Air Flow At the Source of a Leak
The best way to manage defective air flow in and out of buildings is to attend to the problem where it originates, using a combination of the following strategies as applicable:
- Seal the interface points between different envelope materials.
- Support the various parts of the air barrier to resist air pressure.
- Avoid using, or replace air barriers with high air permeability.
- Use materials with the predicted life expectancy of the building.
Valiant Exteriors are becoming Calgary’s go-to-choice for asphalt roofing and all types of siding. Give us a call on (403)829-1661, or post a message by email if you need help with air flowing in and out of your building.
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